Comcast Corp. is escalating its threat to disrupt Walt Disney Co.’s megadeal to buy the bulk of 21st Century Fox Inc.’s assets, a potential move that could reshape the power structure in the entertainment industry.

Comcast said on Wednesday it is in advanced stages of preparing a cash offer that would top Disney’s all-stock, $52.4 billion deal for Fox’s entertainment businesses. One major Fox shareholder is also urging the company to engage with Comcast, adding pressure as the cable giant gets ready to appeal directly to...

RELATED VIDEO

A Brief History of Cable: Creating and Cutting the Cord

The cable industry is undergoing a major transformation, as more Americans cut the cord on their cable subscriptions and flock to streaming services like Hulu and Netflix. So how did we get here? Illustration: Shaumbe Wright/WSJ